This invention relates generally to the field of icemaking equipment or other similar machines for creating frozen blocks from liquid, and more particularly relates to such machines which produce a relatively large block from liquid, and in particular a large block of fruit juice or the like. The invention further relates to the mechanism for handling and transfer of the frozen block.
Machines for freezing liquids into solids are well known. Many such machines are designed to produce a large number of small frozen blocks from a liquid, such as an icemaker within a home refrigerator or a commercial apparatus for restaurants, stores and the like. Other such machines are constructed to produce a single large block of frozen material having a volume of multiple cubic feet, such as a block of frozen fruit juice, where the large block so produced is then handled, stored, transported, etc. as required. A known design comprises a large number of heat transfer tubes which are suspended from a refrigeration distribution manifold. The heat transfer tubes extend into a mold which is provided with either a hinged or removable bottom. Liquid is introduced into the mold and a refrigerant is passed through the heat transfer tubes to lower the temperature of the liquid below the freezing point. Once the liquid is frozen into a large block, the bottom is moved to open the mold and the ice is removed from the heat transfer tubes. Usually a hot gas or other fluid of elevated temperature is passed through the heat transfer tubes to produce a thin layer of liquid on the surface of the tubes, such that the frozen block does not adhere to the tubes and releases easily. The frozen block is often directed onto an inclined ramp, where it slides to a desired handling location.
An example of a freezing apparatus for producing large blocks of frozen liquid is shown in U.S. Pat. No. 5,524,451 to Tippmann. In Tippmann, a four-sided, open-top, closed-bottom container mold is provided to receive the liquid to be frozen, with a large number of heat transfer tubes positioned within the interior space of the mold. The tubes and mold are suspended a distance above the ground greater than the height of the frozen block to be produced. The container is filled with liquid and raised to a height such that the tubes are disposed within the liquid. Refrigerant gas is passed through the tubes and the liquid is frozen. The container mold is then lowered with the frozen block remaining adhered to the heat transfer tubes. A pair of inclined members pivot into position above the retracted container mold, the inclined members being separated by a distance less than the width of the frozen block. Hot gas is then passed through the heat transfer tubes, causing the frozen block to melt in the areas in contact with the tubes. The weight of the block causes it to slide downward from the tubes, such that it falls onto the inclined members and slides onto a conveyor or other handling equipment. The inclined members are removed and the container mold is then refilled with liquid, raised into freezing position, and the cycle is repeated.
Another example of a related machine is shown in U.S. Pat. No. 2,723,534 to Wilbushewich. This device is a machine to make ice blocks, where a walled mold with an open top and a hinged bottom is disposed in fixed relation to the heat transfer tubes. The mold is tapered such that the walls angle outward toward the bottom. With the bottom of the mold in the sealed position abutting the mold walls, water is introduced into the mold and refrigerant is caused to flow through the heat transfer tubes to create an ice block. Once frozen, the bottom is pivoted to the side and hot fluid is passed through the tubes to cause the ice block to release from the heat transfer tubes. It then falls onto a plate mounted onto a movable trolley, the plate being subsequently lowered such that the block and other blocks produced in adjacent molds clear the apparatus such that the trolley can be moved laterally to transport the ice blocks to a desired location.
The major drawback with the Tippmann and Wilbushewich devices, as well as with many other similar machines, is that the frozen block is allowed or required to fall from the freezing mold in a naked state and in a relatively uncontrolled manner, with subsequent handling required to place the block onto pallets or trays for further transport, handling or storage. This is especially detrimental for large blocks, such as a block of frozen juice 48 inches by 56 inches by 57 inches, which is a size suitable for placement and transport on pallets of standard size. Such blocks will weigh thousands of pounds. Additional equipment or labor steps must be employed to place the frozen block onto a tray, pallet or other bottom member so that the block can be wrapped or enclosed to prevent contamination of the product. Direct contact between the frozen block and ramps, platforms or other support members creates a need for frequent cleaning, as friction or ambient temperature effects will cause some melting of the block during the transfer motion. In addition, allowing the block to fall onto a platform or ramp subjects the block to shocks and stresses which can cause the block to crack or split, in which case the block must be removed so as not to disrupt the transport mechanisms.
It is an object of this invention to provide an apparatus which creates large blocks of frozen liquid by providing a walled mold to define an area within which are disposed multiple linear heat transfer tubes, where refrigerant is circulated through the tubes to freeze liquid delivered into the mold, with subsequent distribution of a defrosting material through the tubes to cause the block to release from the tubes, where the mold bottom for the block is raised to create a sealed junction with the mold walls, thereby defining the bottom of the mold, and where the mold bottom and frozen block are lowered in a controlled manner such that the block is not subjected to detrimental shock effects resulting from free fall, the block being removed laterally from the elevator means after the block has been fully lowered. It is a further object to provide such an apparatus where the mold bottom comprises a tray or pallet positioned on an elevator means, where the tray seals with the mold walls to receive the liquid, where once the tray and frozen block are lowered in controlled manner from the mold, the tray and block are together removed laterally from the elevator means such that the tray becomes the bottom of the container for the frozen block.
The invention comprises in general an apparatus for freezing a liquid into a large solid block and subsequently delivering the frozen block, and in particular an apparatus for creating and handling a single large block of fruit juice or the like. A relatively large number of linear heat transfer tubes are suspended vertically from distribution manifolds, where a refrigerant composition, typically a refrigerant liquid of known type such as ammonia or glycol, is directed through the tubes to freeze a liquid, and further where a defrosting fluid of elevated temperature, typically a liquid or gas, is subsequently directed through the tubes to enable the block to separate from the tubes by creating a thin layer of melted material adjacent the tubes. An open-bottom, walled mold, preferably four-sided with the sides angled slightly outward in the downward direction, is provided in a fixed position. Preferably, heat transfer tubes are also disposed within the interior of the mold walls in a serpentine configuration, the serpentine tubes likewise acting in conjunction with the linear heat transfer tubes to freeze and then heat the liquid in contact with the mold walls.
An elevator means, preferably comprising a pneumatic or hydraulic piston, is provided beneath the mold to vertically raise and lower a mold bottom member into sealed contact with the bottom edges of the mold walls. In a first embodiment, the mold bottom member is a generally planar platform component of the elevator means itself, while in a second and preferred embodiment the mold bottom member comprises a tray or pallet temporarily placed on the elevator means, the tray or pallet being removable from the elevator means.
The mold bottom is raised to seal with the bottom edges of the mold walls, and the liquid to be frozen is introduced into the mold. Refrigerant is circulated through the heat transfer tubes to freeze the liquid. When the liquid is frozen into a solid block, the hot fluid or gas is circulated through the tubes to create a thin layer of liquid on the surface of the tubes and the mold walls so that the block no longer adheres to the tubes and the mold walls. The elevator means is then lowered, or more preferably, the elevator means is provided with a passive lowering mechanism, such that the weight of the block itself causes the elevator means to lower into the fully retracted position such that the top of the block clears the bottom of the mold walls. Block removing means removes the block laterally, and in the preferred embodiment removes the tray and the block in combination, onto a conveyor or other handling system for further processing. A new tray is then positioned onto the elevator means, which is raised to seal with the mold walls and the cycle is repeated. Multiple block making apparatuses may be disposed at separate locations along a single conveyor.